Structural and Optical Characteristics of Zn-Rich In2O3-SnO2-ZnO (ITZO) Thin Films Prepared by Radio Frequency Magnetron Sputtering

In-1.2(Sn0.3Zn0.5)O-3 thin films were deposited on glass substrates by radio frequency magnetron sputtering at various growth temperatures. The films deposited at room temperature (RT) and 200 degrees C were amorphous, whereas the films deposited above 250 degrees C consisted of a randomly oriented polycrystalline cubic In2O3 phase. The optical transmittance, optical band-gap, and electrical resistivity increased with increasing substrate temperature. The d-spacing of the polycrystalline films increased from 10.088(2) to 10.118(1) angstrom when the films were grown at 250 degrees C and 400 degrees C, respectively. An EDX analysis showed that the Zn content in the films decreased from 27.04 to 13.36 at% as the deposition temperature increased from RT to 400 degrees C. The variation in the electrical and optical characteristics was attributed to a decrease in the Zn content, which was caused by the higher vapor pressure of Zn compared to In and Sn at high substrate temperatures.